1. Field of the Invention
The invention relates to a crane gear for the transport of web rolls with a winding core, provided with a passage hole, preferably for the transport of paper rolls, with a support frame, attached to a cable, with receiving units.
2. Description of the Related Art
Web rolls, for example made of paper, that can exhibit a weight of one ton and more, are usually transported by means of floor conveyors, for example fork lift trucks, provided with a carrying mandrel, in order to put them, for example, into unwinding units. Paper webs are drawn off, for example, from paper rolls, suspended in unwinding units, in order to produce from them tubular sections for the purpose of producing sacks or to print on them in the printing machines. It is difficult, especially under crowded room conditions, to maneuver a roll of paper hanging from a receiving mandrel of a fork lift truck.
The invention proceeds from the recognition that in the typical operations and production halls there are cranes, which can be moved to arbitrary places in the halls. Moreover, it is easier to maneuver the paper rolls, hanging from a crane hook; and thus it is easier to transport them to the unwinding units and optionally they may be conveyed away from the unwinding units.
Therefore, the object of the invention is to provide a crane gear of the class described in the introductory part of the specification, into which it is easy to suspend the web rolls and from which it is easy to remove again the web rolls from the same.
The invention solves this problem in that the support frame of the crane gear comprises an upper yoke carrier with legs, which project in the downward direction and whose ends are provided with hooks. A support rod, slid through the passage hole, can be suspended from the legs. Thus, the inventive crane gear comprises in its simplest design a U-shaped support frame with downwardly projecting legs, with which the ends of the support rod that protrude on both sides beyond the passage hole of the web roll can be coupled together.
For the purpose of attaching the web roll to the support frame and also of uncoupling it again from the same, a preferred embodiment provides that the yoke carrier has a passageway therethrough in which a boom rod can be slid. One end of the boom rod that projects beyond the yoke carrier is connected to a support arm, projecting in the downward direction. One end of the support rod can be coupled to the support arm, while the other end of the support rod lies in such a manner in the hook of a leg that the support rod can be forced into engagement with the hook of the other leg by moving the support arm and the boom rod through the passageway in the yoke carrier. In this inventive improvement, the outer end of the support rod is connected to the support arm of the extended boom rod, whereby the other end of the support rod rests in the hook of a leg so that the crane gear can be aligned in such a manner in relation to the paper roll over the crane that the support rod lies in front of the passage hole and aligns with said hole. By simply moving the support arm with boom, the support rod can be slid in such a manner through the passage hole of the web roll that it engages in such a manner with the hook of the other leg that the legs enclose the paper roll and the support rod is suspended from the hooks.
The eye of the crane gear is located in principle in the vertical center plane between the legs of the support frame. If, however, the boom is extended to one side, said boom exerts on the support frame a moment that tries to swing the support frame into an inclined position, in which it is difficult to simply attach the web roll. Therefore, a further development of the present invention provides that a guide rod, which runs parallel to the yoke carrier, is attached to the brackets of the yoke carrier. On the guide rod can be site a counterweight, which is connected in such a manner to the boom rod by means of connecting means that the crane gear is located, in almost all outward thrust positions of the boom rod, essentially in the balance of moments about a horizontal cross axis, running through the eye. Thus, a support frame that is provided with the inventive counterweight can be coupled in a simple manner to the web roll, because in every position of the boom the legs, provided with hooks, are located, as a rule, in their vertical position.
Preferably the connecting means comprise a cable, whose ends are fastened to the yoke carrier or the brackets and whose strands are reeved, like a block and tackle, on both sides of a fixed point to the boom rod between rollers, located on both sides of the counterweight and the yoke carrier or the brackets. In this design the counterweight is automatically coupled in such a manner to the boom rod by means of the cable reeving that, when the boom rod is moved, the counterweight exerts a movement, opposite the movement of the boom rod.